Hectograph blanket having an ortho acidic bonding agent



April 29 194i v J. BJGRKSTEN 2,240,029

HECTOGRAPH BLANKET HAVING AN ORTHO ACIDIC BONDING AGENT Filed Jan. 10, 1940 Patente .lichen lhiorksten,

Chicago, fil., assigner to llllitto,

lincorated, ihicago, llil., a corporation of West Virginia lppiication January lil, 19M, Seriali No. 313,189

(Cl. ill-3MB) ii Claims.

The invention relates to hectograph blankets and to4 methods of preparing the same.

Hectograph blankets generally comprise a gelatirious copy mass secured to a iiexible backing. Heretofore the backing has been secured to the' copy mass by meansv of a bonding agent Whichhas tanning characteristics suchas, for err-ampie, linseed oil or other drying oils, or mixtures of cellulose esters and 'tanning agents such as alum, phenol, resorcinol, formaldehyde, and the like. Such bonding. compositions have the inherent disadvantage that they cause progressive tanning of the overlying hectograph copy mass, with the result that after a period of time the hectograph copy mass becomes so hard that it is not commercially usable. In some cases, nontannin'g bonding compositions have been used, Vas for example the sulphonated castor oil disclosed in Hoskins Patent 2,098,662.L These sulphonated oil compositions. while in general suitable, are dimcult to prepare and apply so as to obtain uniform results.

rI have discovered that non-tanning ortho carboxylic acids, non-tanning ortho anhydrides, and non-tanning salts of ortho carboxylic acids which dissociate in water or alcohol to form the corresponding acid are partlcularlyeective bonding agents when vused alone or in combination with other ingredients as the intermediate bonding lm or layer of a hectograph blanket. Such ortho acidic substances alloy.r the production of hectograph blankets quickly and economically,

and when used alone or in conjunctionwith other non-tanning substances as the intermediate bonding nlm or layer, provide a hectograph blanket which remains soft and commercially usable over a long period of time.`

Among the ortho acidic substances suitable for the practice of my invention are phthallc anhydride, oxalic acid, camphoric anhydride, tetrabromphth-alic anhydride, salicylic acid, ortho naphthenic acids, and salts of ortho` naphthenic acids.

The ortho acidic substances may be used alone, but generally are admixed with other materials, preferably non-.tanning ingredients.

The preferred bonding composition is a. coating composition comprising a cellulose ester such as cellulose acetate, or a nitrocellulose, a volatile solvent for the cellulose ester such as ethyl acethe ortho portion.

The invention is further illustrated in conjunction with the accompanying drawing in which- Fig. 1 is asectional view of a hectograph blanket illustrating one embodiment of my invention, and c Fig. 2 is a sectional view of a modified form of hectograph blanket embodying my invention.

Referring to the drawing, and particularly to Fig. l in which a preferred embodiment of the invention is illustrated, the reference character i is a gelatinous copy mass secured by means of a hlm or layer 2 comprising an acidic substance to a flexible backing consisting of a paper, cloth or other fabric base i coated on both sides with a relatively non-adhesive lacquer t and ii. In the embodiment of the invention shown in Fig. 1, the bonding layer 2- preferably comprises one of the usual cellulose derivative lacquers containing an ortho acidic substance.

In the embodiment of the invention shownfin Fig. 2, the hectograph blanket comprises a gelatinous copy mass i secured to a paper, fabric or similar backing il which is impregnated with an ortho acidic substance alone or in xture 'with other ingredients, preferably of a non-tanning character. i

' In the embodiment of the invention shown in both Fig. l and Fig. 2, the portion of the bac remote from the copy mass is covered with lacquer or similar substance illustrated by the layer 5; rll'his outer covering is not essential, but is preferable when the hectograph blanket is `to be used in the form of a roll, in order to avoid excessive adherence of the backing to the hectograph copy mass.

, tate and a substance having carboxyl groups in A To more clearly set forth the practice lnaccordance with the invention and to more specically point out the nature of the product and process contemplated thereby, several specific illustrative examples are hereinafter set forth, it being understood that these. examples illustrate several embodiments which have given satisfactory results and are not intended to restrict the invention thereto.

Example I.-4% of phthalic anhydride Wasi dis-y solved in 10 parts of ethyl acetate. This solution was added to 90 parts by Weight of a conventional nitrocellulose lacquer having a solid content of 37%. This solution was applied to the cloth under tension with a doctor knife. After drying, a convention duplication mass was poured onto the cloth at 70 C., and the mass was kept in melted state in contact with the cloth for 20 mlnutes. The rolls thus prepared were tested and found satisfactory.

This solution was added to a lacquer consisting oi 18% of 1/2" nitrocellulose, 40% of toluene and 42% of ethyl acetate. 10 parts by Weight of micronized kaolin were admixed. This composition was applied to rope paper by means of a doctor knife. Hectograph mass was applied to this coated paper at a temperature of 50 C, and

maintained at that temperature until a sample on examination showed .that bond had been formed.

Similar results were obtained with other ortho acids and salts thereof in lm forming solutions such as those stated above. For example, the following acidic substances were tried with positive results: salicylic acid, ortho naphthenic acids, and the sodium salts of ortho naphthenic acids. In fact, every acidic substance tried under Vvarying conditions proved to be, to some extent at least, suitable for the purposeslof this invention, as set forth in the co-pending application of Robert C. Bour, Serial No. 312,929, led January 8, 1940, entitled Hectograph blankets having acidic bonding agents, but it was1 my observation that the ortho acidic materials were in general improvements over the acidic materials in which the carboxyl group was absent from the ortho portion. Thus, the following acidic materials were found operable: sebacic acid, oleic acid, triethanolamine oleate, erucic acid, crotonic anhydride, camphoric anhydride, malic acid, lactic acid and acetic acid.

From the above examples it is apparent that the ingredients, proportions, and procedures may be varied within wide limits without departing from the spirit' or scope of 'the invention. In evaluating ,the lprobable influence of such variations on the quality of bond obtained, the following may be of guidance:

Almost any carrier substance may be employed'. It is not necessary to use nitrocellulose lacquers, other films vare suitable, whether the lm forming material is a resin, a gum, a protein such as zein or casein, acetyl cellulose, or inorganic colloid such as bentonitic clays or the like. Generally, the hectograph mass should not be applied until the bonding film is well dry. Even traces of some lacquer solvents may interfere with the bonding.

Agitation or, turbulence in the hectograph mass, after application to the mass assists in lforming a good bond A controlling factor of the bonding qualities the hectograph mass, before the latter congeals.

Since the other factors may be varied so widely without departing from the invention, it is impossible to give any specic range for the time of contact. However, it is easy to determine the time of contact 'necessary for each set of conditions; by the following simple test: hectograph mass is poured onto the backing material carrying a bonding illm of this invention. The backing material is kept at a temperature above the melting point of the mass for a certain time and is then allowed to cool. The next day one can Areadily ascertain,- by trying to pull voff the iilm of hectograph mass, whether or not this film adheres to the backing, or benda If it does not bond, the test is repeated allowing a longer time'of contact between the backing and the v hectograph mass in the melted state; increasing the time of contact in melted state until bond sion of the gelatin. So far as is known, all ortho acidic substances are operable, although some, as has been heretofore pointed out, give better resuits than others.

While there have been shown and described certain embodiments of the invention, it is to be.

understood that it is capable of many modications. Changes, therefore, may be made without departing from the spirit and scope of the invention as described in the appended claims, in which it is the invention to claim all novelty inherent in the invention as broadly as possible, in view of the prior art.

Iclaim 1. In a hectograph blanket comprising a gelatinous copy mass and abacking, means for securing the copy mass to the backing comprising an ortho organic acidic substance.

2. In a hectograph blanket comprising a gelatinous copy mass and a backing. means for securing the copy mass to the backing consisting of a. non-tanning composition comprising a substance selected from the group consisting of ortho carboxylic acids, ortho anhydrides and salts thereof which dissociate in Water to form the corresponding ortho carboxylic acid.

3. A hectograph blanket having a copy mass and a backing, the copy mass and the backing being bonded together by a bond comprising an orthovorganic non-tanning acidic substance.

4. A hectograph blanket having a copy mass and a backing, the copy mass and backing being bonded together by a bond comprising a cellulose derivative and an ortho organic acidic substance.

5. A hectograph blanket comprising a gelatinouscopy mass, a backing and an intermediate bondingV layer comprising' a cellulose derivative and an ortho organic anhydride. f

6. A hectograph blanket comprising a'gelatinous copy mass, a backing andan intermediate bonding layer' comprising a cellulose and phthalic anhydride.

7. A hectograph blanket comprising a gelatinous copy mass, a backing and an intermediate bonding layer comprising a cellulose derivative and a salicylic acid. i

8. .A hectograph blanket comprising a copy mass, a web base coated on the side remote from the copy mass with a. relatively non-adhesive composition, and secured to the copy mass by a non-tanning composition comprising a cellulose derivative and a non-tanning ortho organic acidic substance.

9. The method of preparing a hectograph blanket which comprises applying to a backing a coating composition of a .non-tanning ortho organic acidic substance to form a flexible bonding nlm,

derivative' 

